This application is a continuation of international application number PCT AT01/00114, filed Apr. 17, 2001.
1. Field of the Invention
The present invention relates to a running gear for a rail vehicle comprising at least two wheel sets mounted in wheel set bearings, said wheel sets having axles, wheels and a chassis frame, the chassis frame being provided with two longitudinal sole bars and with at least one cross-member located therebetween and connected to the sole bars via at least two articulations, whereby the longitudinal sole bars and the cross-member can be displaced relative to one another on a plane parallel to the rail plane.
2. Description of the Prior Art
The build of running gears with a rigid chassis frame often require complicated solutions in order to achieve the required security against derailment. This is mainly the case when such type running gears are provided with a drive. As the chassis frame is hereby usually provided with a brake suspension link and an engine console of its own, problems may arise with regard for example to the longitudinal stiffness of the chassis frame, the primary spring stiffness, and so on. Furthermore, the loads rigid chassis frames are subjected to in practical operation must be deviated by means of complicated constructions in order to achieve compliance with existing safety regulations, which may result in very high un-loaded weight of the running gear.
The above mentioned problems can be avoided hinge-linking the longitudinal sole bars and the cross-member of the chassis frame. This allows the longitudinal sole bars to align in the direction of travel when the vehicle is threading a curve for example, which reduces the chances for derailment as compared to rigid chassis frames.
Such a running gear with a H-shaped, deformable frame and consisting of two longitudinal sole bars and one cross-member is described in DE 43 06 848 A1 and in EP 0 409 128 A1. Lateral forces are thereby introduced in the chassis frame via wheel set bearings that are rigidly connected to the longitudinal sole bars.
WO 90/11216 discloses a running gear with an articulated frame provided with at least one cross-member which is arranged between two longitudinal sole bars and sprung relative to said sole bars. In this case as well, the lateral forces that may be produced by steering are introduced through wheel set bearings which are rigidly connected to the longitudinal sole bars.
In the running gears mentioned herein above, the lateral forces that may be generated when the vehicle travels around a curve are introduced into the chassis frame by way of wheel set bearings that are connected to the longitudinal sole bars of the chassis frame; said chassis frame should be capable of resisting as much as possible to deformation due to these lateral forces in order to further reduce the chances for derailment.
The disadvantage of the prior art embodiments is that they do not permit to achieve the desired stiffness to lateral forces in an articulated chassis frame on account of its design.
It is therefore an object of the invention to provide an articulated chassis frame that is as resistant as possible to deformation due to lateral forces that may be generated when the vehicle is traveling around a curve for example.
The solution to this object is a running gear of the type mentioned herein above in which the wheel set bearings are connected to the, or to the respective one of the, cross-members of the rail vehicle.
In the running gear of the invention, the occurring lateral forces can be introduced directly into the corresponding cross-member by way of the wheel set bearings. Accordingly, the lateral forces are not introduced, like in the prior art running gears, into the longitudinal sole bars of the chassis frame. Since the cross-member is provided with a considerably higher deformation resistance to the occurring lateral loads than the longitudinal sole bars, the stiffness properties of the running gear are substantially enhanced over conventionally used running gears.
If two wheel sets having at least one cross-member arranged therebetween are provided, the wheel set bearings are configured, in an advantageous variant of the invention, to form link brackets, said link brackets being rotatable parallel to the axles of the wheel sets about prolongations of the cross-member.
A particularly good transmission of the lateral loads is achieved when the wheel set bearings are connected to the, or to the respective one of the, cross-members in such a manner that it is impossible for the wheel set bearings to get twisted relative to the corresponding cross-member about an axis normal to the rail plane.
In another advantageous embodiment the wheel set bearings are rigidly connected to the, or to the respective one of the, cross-members. An advantageous variant of this embodiment consists in providing four wheel sets, two respective wheel sets forming a pair, one cross-member being arranged between the two pairs of wheel sets. In order to achieve the best possible introduction of forces from the wheel set bearings into the cross-member in this embodiment, two wheel set bearings, located one behind the other in the direction of travel, of one respective pair of wheel sets are made in one piece.
In another variant, two wheel sets are provided, a cross-member being arranged therebetween. In this variant, a drive for the running gear may be arranged on the cross-member.
In another embodiment, each wheel set is provided with a drive for the running gear, said drive being coaxially arranged on the axles of the wheel sets.
In this embodiment it is advantageous when two consecutive drives are connected by means of two rods arranged one above the other substantially parallel to each other.
In order to relieve the wheel sets of their function of longitudinally entraining the chassis frame, it is furthermore advantageous to provide brakes in the region of the axles of the wheel sets. As a result thereof, the connection of the wheel sets with the, or the respective one of the, cross-members may be designed exclusively to achieve the required degree of lock of the wheel set about an axis normal to the rail plane. In an advantageous development of this variant, the brakes are directly connected to the drive.
In an advantageous embodiment, the wheel set bearings are arranged between the wheels.
In another variant, the wheels are arranged between the wheel set bearings.
In an advantageous embodiment of the articulations located between the cross-member and the longitudinal sole bars, the articulations are configured to form pendulum joints. The articulations are variable in height, which makes it possible to adjust the angle of inclination of a car body relative to the running gear.
In another embodiment, the articulations are configured to form ball-and-socket joints.